Planning my first LED lighted sign, laying awake at 3 am thinking about it I wondered how to do signs in colors. Does one use only clear plastic and count on the color of the LED's to give color, or does one use colored plastic? And if one was to use colored plastic, would lighter tones or darker tones work best? Would like to do purple, green, red at least...

If you don't have any experience of this sort of thing then stick to clear Fred, it will probably work to some degree with a tinted acrylic but getting it right would probably take a fair bit of working out

Not sure as I mostly use 3/8" plexi and that is only available in clear FAIK. That plus its tough to think of any sales application, other than random novelty, for a colored plexi sign.Any tinting mutes light transmission, I have tried tinted lexan and is nearly useless for edge lit signs ,,, But tinted lexan is specifically designed to block light transmission so that shouldn't have been a surprise for me. I'd say for sure stay away from the darker tints, attempts to light will be entirely underwhelming.

Wouldn't hurt to try if you like to experiment and have a supplier, I'd say keep your expectations low and only use white LED's. Wouldn't seem to make much sense, for instance, to try lighting a light blue or yellow tint with a red or green LED.

To summarize, I think the lighter tints would be doable. Yellow for example would indeed look yellower than clear with a yellow LED, but won't be as bright and of course, you are limited to that one color.Also, wouldn't not try going thinner than .25, .125 is tough to light up and can be tough to make bases for.

fred ruppert wrote:Samples on their way, any suggestions on bits and on feeds/speeds so I cut / not melt the plastic when I cut the outside shapes?

I truly cannot believe how large a difference the right tool for the material makes. I just cut some pieces out of 3/8" Lexan with these bits and the edges where cleaner than any others I have ever done. My method is slow my spindle down to 8000 rpm feed rate down to 50 IPM and keep the chips blown away or brushed away. No sanding whatsoever required once they come off of the machine.

I truly cannot believe how large a difference the right tool for the material makes. Well you should, I told you that ages ago

Fred as Dwayne has said using a bit that is made to cut plastics will make a big difference, they generally do cost more but like Dwayne I think they are worth the extra money, I don't use them for cutting anything but acrylic to try & make them last as long as possible Single flute cutters work best for me as I find it easier to get the speed & feed settings I need to cut acrylic well.

If you buy the right bits then the tool manufacturer should provide speed & feed settings for the bits, use those as a starting point only to tune your own machine by experimenting on a scrap piece

Well I bought the bit and it did a very nice job, but there are still some 'chatter' marks. Is this good enough? or is it good enough for the the next recommendation which was either MAP gas or buffing to get a finer finish.

Thanks for the positive comment on the LEDs to use for colored acrylics

Hard to tell if its good enough without a pic - Generally, flaws show up like a beacon on lit acrylic and I have a low tolerance for flaws, you may be different. Edge chatter is some of the worse visually, I would not accept it.

I'd advise doing cutouts [assuming square] with a table saw and not the cutter. With the proper blade [not cheap, 72-80 tooth triple chip] they come out virtually chatter free but still need sanding and polishing to bring to perfection.Using gas is the poor mans solution, better than nothing. Will polish the edge to some degree but may not do anything about chatter if it extends past the edge.

I have that blade in my circular saw and it works a charm, but I still think that edge would need some additional work. The router bit was my choice for cutting out the other three sides so that I could get some radii in the corners.

The chatter from the router bit smoothed out with a little work with 320 sandpaper. When I went up to 600 and 800 grit paper, the paper loaded up fairly quickly, so I don't see sanding as the means to the end edge.

I was going to experiment with MAP gas to see the effect, but you are giving me an impression that is a lazyman's way...the alternative that I also have yet to try is using a buffing wheel. I will probably get a buffing wheel anyway in case I get some minor scratches on the main surfaces - is that your preferred way to get a perfect edge? Again, I don't see the special blade (that I got for cutting Corian without splinters) as the end all solution.

....but I don't know when is good enough, good enough...a common problem likely.

No, "poor mans" is a common phrase meaning there are better solutions available. Didn't mean to censure to people who use this method, but it is better than nothing and people either work with what they have or pony up to get better more efficient tools.I used gas before I invested in a $500 buffer. For sanding I use an orbital with 120, then a mouse sander with 160 which leaves them perfectly smooth.Sometimes I leave them like this for a frosted look, most often I'll buff them to a glass finish with the buffer.You'll have limited results with any hand held buffer - For one, very tough to hold material down while buffing. I bought a top of the line Dewalt hand held buffer, instead of bringing it to the material I ended up strapping it down securely to a bench and bringing the material to it.Had no where near the balls to do the job and turned buffing wheels to shreds in no time, not the right tool for the job - I visited a friend who actually sells and shapes plexiglas for a living and inquired about buffing, he showed me his Baldor and I fell instantly head over heels madly in love.

Thinking that perhaps I could get results like him on the cheap I tried a cheaper 3/4 HP buffer off Amazon first, 3/4 hp buffer is a 3/4 hp buffer I thought. Nope, it nearly shook itself apart so, as I do alot of plexi, I bit the bullet and got the Baldor, could not have made a better move and have not used flame on edges since. Comes in handy for more than just plexi too obviously.

Using MAPP, best to experiment on scrap to get a feel for it if you have never done it. Idea is to keep the flame moving, like spray painting. When its flash point is reached it will ignite quickly, bubbling, turning black and generally ruining the project. Propane can be used too with less risk of flashing but will take longer. Best to do a couple quick passes on an edge, turn and do the others ect, that way they have a chance to cool down and you are not just standing there whistling Dixie waiting for them to cool.You can kinda tell when its "done" after doing a few.